By 2019 pretty much everyone knows that Musk is a person who makes extremely ambitious predictions, projections, timelines, etc, and tries to meet them. Almost anyone in that situation will have a low hit rate. There's no sin to pay for, this is how he chooses to work and structure his businesses. Investors tend to be very happy with the results. To them, making a large number of ambitious goals and meeting some of them is still very worthwhile.
If you want to invest in companies where they make no such predictions, and the CEOs are never wrong, you are welcome to buy GE and follow their CEO on twitter. He has never, ever made a wrong prediction: https://twitter.com/larryculpjr